Food supply drives reproductive strategies in sharks, skates and rays Published on: 9 September 2025 Sharks, skates and rays adapt their growth and reproduction to changing food availability, a new study reveals. Led by Âé¶¹´«Ã½, the study analysed how many young and how quickly a generation is replaced – known as reproductive output and generation turnover in 151 species of sharks, skates and rays. The results reveal that these species’ life strategies are shaped not just by their evolutionary background, but also by how much food they get. , the findings show that when there is more food available and feeding levels increase, species tend to produce more offspring. Reef Shark Linking demographic data with energy-budget theory The researchers also found that widely used indicators, such as population growth rate, don’t always offer a full picture of how these species will respond to pressures such as climate change or fishing. In addition, the authors found that conservation risk (as measured by the IUCN Red List) wasn’t linked to a species’ reproductive output (how many young they produce) or generation turnover (how quickly newborns mature and produce the next generation of offspring). By contrast, the approach of integrating demographic data with energy-budget theory, which was used in the study, provides a new way to test different fishing scenarios and better estimates what levels of fishing can be sustainable. This method combines information on how sharks, skates and rays – collectively known as elasmobranchs - allocate energy to growth, survival and reproduction, and uses it to define a ‘life-history space’ informed by species energetics and feeding. The result is a quantitative, mechanistic basis for predicting how changes in food availability or fishing pressure could shape species’ life strategies. Giant devil ray Understanding how species respond to population declines Study lead author, Sol Lucas, a PhD researcher at Âé¶¹´«Ã½’s School of Natural and Environmental Sciences, said: “Our findings show that sharks, skates and rays are flexible in their growth and reproduction, adjusting to the food availability in their environment. “These life-history strategies shape population growth and recovery, making them vital for understanding how species respond to population declines. Looking ahead, by linking energy budgets to life-history strategies we can gain a clearer picture of which species are most at risk from pressures such as overfishing and environmental change.” Study lead author, Dr Isabel Smallegange, Senior Lecturer in Population Biology at Âé¶¹´«Ã½’s School of Natural and Environmental Sciences, added: “In marine ecology, understanding how feeding dynamics influence life-history strategies is crucial, especially for elasmobranchs, which face heightened conservation concerns worldwide. However, comparative data across species and feeding regimes have been scarce. “To address this gap, our study integrates demographic data with energy-budget theory to analyse 151 elasmobranch species, exposing how varying feeding levels shape developmental and reproductive strategies. By revealing previously unappreciated plasticity in life-history traits, this research brings fresh insight into how these species may respond to ecological challenges and offers a more informed basis for effective conservation actions.” The authors recommend further research to explore whether changes in the environment make different species more flexible in how they grow and reproduce, and how this flexibility affects their survival and ability to cope with change. Reference Lucas, S., P. Berggren, E. Barrowclift, and I. M. Smallegange. 2025. “Changing Feeding Levels Reveal Plasticity in Elasmobranch Life History Strategies.” Ecology Letters 28, no. 9: e70201. Latest News Local knowledge can improve early warnings of glacial lake floods Local knowledge, improved evacuation preparedness and resilient mobile phone-based communication channels can enhance Early Warning Systems to reduce loss of life during glacial lake outburst floods. published on: 3 August 2026 Funding boost moves landmark cancer research centre a step closer A £1.25 million grant from the Wolfson Foundation to Âé¶¹´«Ã½ has brought the Sir Bobby Robson Institute a significant step closer, giving a major boost to its fundraising campaign. published on: 3 August 2026 Statement on potential unauthorised data access Information about a potential unauthorised data access. published on: 30 July 2026 Facts and figures